Are you sure of this one hundred percent? It seems to me impossible to say such things, because it's just unpredictable. There may be a new coin that will become very popular and its price will compete with Bitcoin, why not?
I really don't think so , if the price of bitcoin crashes so hard that will also make the alts crash with it . Cryptocurrency reputation is based on bitcoin , all the new commers in the crypto world ,first they tought the only digital currency is bitcoin and then they start to learn more . So bitcoin is the base and i don't see any alt tapping it ,not for a long time.